There is a 288 page PhD thesis by Stephen Gaunson called Ned Kelly & the Movies 1906-2003: Representation, Social Banditry & History available online.
It is in PDF form (it took me almost an hour and a half to download it on dialup!). It was well worth it, though!
There are also quite a few interesting scene captures, photos and illustrations related to the Kelly saga included.
You can find it at: